Did you try this one in B&W? A strong yellow filter would make that sky almost disappear, and with that kind of lighting the mountain would really be amazing (even more so than it is now )
Hi Neil ... As I'm not specialized in BW I didn't try it yet. But perhaps I know a solution in photoshop: Strong polarizer-effect makes the Red-Channel black as well, so perhaps I upload another version later. Thanx for this great hint!!